Impairment index versus T -score averaging in neuropsychological assessment.

Abstract

Neuropsychological data were obtained on 81 patients with cerebral lesions and on 87 patients presenting signs and symptoms of cerebral dysfunction but who received nonneurological discharge diagnoses. Two methods of combining neuropsychological test results were compared for percentage of accuracy in classifying subjects into appropriate groups. A standard deviation averaging method using 2'-score conversion tables for raw score data was found to be superior to the Halstead impairment index for the nonncurologic group only. The difference was attributed to the tendency of the Halstead index to misclassify older, normal subjects as brain damaged. The cutting score used by the averaging method (-1 standard deviation) was considered to be pathognomonic in that very few nonneurological subjects scored lower than this point.

Neuropsychological stability in multiple sclerosis.

“…Normative data for many of the above-described tests have been provided by Kiernan and Matthews (1976). The availability of these norms permits the transformation of raw scores on individual tests into T scores (M = 50, SD = 10), thereby providing a mechanism for comparing the experimental subjects' performances against "normal expectation."…”

Tourette syndrome and neuropsychological performance

“…Conversion of the data to a common metric permits comparison of performance between measures, and also permits computation of summary scores (such as mean Tscores). Such T-score averaging has previously been shown to be useful (14). Although a control group was not directly examined, conversion of the data to norm-based T-scores represents an implicit comparison with control values.…”

Effects of patient age on neuropsychological test interpretation.

“…The accuracy rate in the interpretation of the normal elderly adult test performance was quite low and yet quite consistent with the literature on elderly persons' test performance. This literature suggests that misclassification and misinterpretation are likely to occur in the evaluation of elderly adults (Bornstein, 1986; Davies, 1968; Kiernan & Matthews, 1976; Price et al, 1980).…”

“…The use of such norms can result in incorrect interpretations of test findings and lead to inappropriate recommendations for an elderly patient. For example, several studies have shown that a large percentage of normal elderly subjects are misclassified as brain damaged when standard adult norms are used (Anthony, Heaton, & Lehman, 1980; Bak & Greene, 1980; Bornstein, 1986; Cauthen, 1978; Davies, 1968; Ernst, 1987; Heaton, Grant, & Matthews, 1986; Kiernan & Matthews, 1976; Long & Klein, 1990; Mack & Carlson, 1978; Pauker, 1980; Price, Fein, & Feinberg, 1980). Reitan (1955a), in fact, demonstrated that after the age of 45, many normal persons score in the impaired range on the Halstead–Reitan Neuropsychological Battery (HRNB).…”